Mineral and Phytochemical Profiles and Antioxidant Activity of Herbal Material from Two Temperate Astragalus Species.

Only a few species of the large Astragalus genus, widely used for medicinal purposes, have been thoroughly studied for phytochemical composition. The aim of our research was to investigate the rarely studied species A. glycyphyllos L. and A. cicer L. for the distribution of mineral elements and phytochemicals in whole plants at two growth stages and in morphological fractions. We also investigated the capacity of the plant extracts to scavenge 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals and to chelate ferrous ions. Chemical composition and antioxidant properties depended on species, maturity, and plant part. Herbal material of A. glycyphyllos was richer in Fe, total phenolics, and flavonoids, whereas extracts of A. cicer showed a higher antioxidant activity. Young plants had more isoflavones, showed greater quenching of DPPH radicals, and exhibited better mineral profiles than flowering plants. Among plant parts, leaves were the most valuable plant material according to most characteristics investigated. Isoflavone concentration in flowers was lower than in leaves and stems. None of the Astragalus samples contained detectable amounts of the alkaloid swainsonine. The study demonstrates the potential of plant material from two Astragalus species as a valuable source of iron, phenolic substances including isoflavones, free-radical scavengers, and Fe2+ chelators for pharmaceutical use.

Perennial legumes as a source of ingredients for healthy food: proximate, mineral and phytoestrogen composition and antibacterial activity.

ABSTRACT: Perennial legumes have been used as edible or medicinal plants since ancient times. The focus of the current study are perennial legumes-Trifolium pratense L., T. medium L., Medicago sativa L., M. lupulina L., Onobrychis viciifolia Scop., Astragalus glycyphyllos L. and A. cicer L.-of branching stage as a potential source of value-added ingredients for healthy food. Freeze-dried samples were analysed for proximal composition, mineral, isoflavone and coumestrol contents as well as for antimicrobial activity. Legumes were protein-rich (23.0/100 g on average). Mineral contents in 100 g of plant dry matter averaged: K 2.64 g, Ca 1.81 g, Mg 0.475 g, P 0.324 g, Zn 2.76 mg and Fe 37.8 mg. According to the total amount of phytoestrogens, the species ranked as follows: T. medium (34.4 mg/g) â‰« T. pratense â‰« O. viciifolia ≥ M. sativa = A. cicer = M. lupulina ≥ A. glycyphyllos (0.207 mg/g). Extracts of legumes, especially that of O. viciifolia, exhibited noticeable potency to inhibit the growth of Gram-positive and Gram-negative bacteria. Perennial legumes of branching stage can be used as protein, mineral and phytoestrogen rich source for food ingredients and supplements.

Enantioselective determination of protein amino acids in fertilizers by liquid chromatography-tandem mass spectrometry on chiral teicoplanin stationary phase.

High-performance liquid chromatography on a glycopeptide antibiotic teicoplanin-based chiral stationary phase coupled with tandem mass spectrometry was developed for fast and reliable enantioseparation and determination of protein amino acids in hydrolyzed fertilizer samples. The effect of the mobile phase parameters (type and content of organic modifier and pH) and the column temperature on the enantioselectivity was investigated. Under optimized conditions, the majority (15 of 19) of d/l-amino acid pairs were resolved with a resolution factor (Rs) higher than 1.5 with a run time of 15 min. A triple quadrupole tandem mass spectrometer operating in multiple reaction monitoring mode with an electrospray ionization (ESI) ion source was employed for detection. The method was validated in terms of linearity, limits of detection, limits of quantitation, precision, and accuracy. Linear responses were obtained with determination coefficients higher than 0.998 for all analytes, and limits of detection were from 0.04 to 0.24 µg/mL. Sample spike/recovery experiments gave recovery values ranging from 73% for d-threonine to 116% for L-tryptophan. Relative standard deviations for inter- and intraday precision experiments were lower than 21.7%. The developed method was successfully applied for determination of the free amino acid enantiomers in five commercially available hydrolyzed protein fertilizer samples.

Mixed-mode SPE for a multi-residue analysis of benzodiazepines in whole blood using rapid GC with negative-ion chemical ionization MS.

A sensitive and selective method for simultaneous quantitation of 15 benzodiazepines in human whole blood using rapid GC with negative-ion chemical ionization MS is proposed. A mixed-mode cation-exchange polymeric sorbent was used for SPE. Different extraction solvents or mixtures of solvents of different compositions for elution of the adsorbed analytes, and washing steps for eliminating interferences in the column were tested. Analytes were eluted from the column using 5% v/v NH4 OH in methanol. A derivatization step using different silylation reagents, time, and temperature was tested. Extracts from SPE were silylated by a mixture of N-(tert-butyldimethylsilyl)-N-methyltrifluoroacetamide, acetonitrile, ethyl acetate, and subjected to gas chromatographic analysis. The LODs of 15 benzodiazepines in whole blood samples ranged from 0.24-0.62 ng mL(-1). The RSDs of samples used for three different quality control concentration levels were lower than 7.0%, and the accuracy ranged from 89.5 to 110.5%. The results show that the developed method is accurate, sensitive, selective, and very fast. Finally, the applicability of this method for determination of trace concentrations of several benzodiazepines in real blood samples has been demonstrated.

Retention behaviour of imidazolium ionic liquid cations on 1.7 µm ethylene bridged hybrid silica column using acetonitrile-rich and water-rich mobile phases.

The potential of 1.7 µm ethylene bridged hybrid silica phase was investigated for the separation of twelve imidazolium-based ionic liquid cations. U-shaped retention profile was observed for all solutes with an increase in retention at both low and high acetonitrile content. Chromatographic behaviour of imidazolium cations in both hydrophilic interaction chromatography (HILIC) and per aqueous liquid chromatography (PALC) modes was studied by varying key parameters such as buffer concentration and pH, acid additive, organic modifier and column temperature. Experimental data provided some evidences that under PALC conditions cationic solutes are retained predominantly by mixed hydrophobic/ion-exchange interactions. In the HILIC mode, both partitioning and ion-exchange interactions are responsible for the retention of solutes. Compared to PALC, HILIC provided significantly higher efficiencies with less or even no peak tailing, better separation selectivity and greater resistance to overload. In PALC mode gradient elution was required to achieve adequate retentivity of all solutes but selectivity was not sufficient to distinguish between solutes with very similar hydrophobicity. In contrast, under HILIC conditions twelve solutes were almost completely resolved in less than 4 min by using isocratic elution. Summarizing, it could be concluded that ethylene bridged hybrid silica column providing a dual retention mechanism offers the possibility of selecting between the two retention modes with opposite separation selectivity, just by changing the composition of the mobile phase.

Matrix solid-phase dispersion extraction of carbadox and olaquindox in feed followed by hydrophilic interaction ultra-high-pressure liquid chromatographic analysis.

A new method involving matrix solid-phase dispersion (MSPD) extraction and hydrophilic interaction ultra-high-pressure liquid chromatography (HILIC-UHPLC) with photodiode array detection was developed for the determination of carbadox and olaquindox in feed. Separation of carbadox and olaquindox was achieved within 1 min on the 1.7 microm Acquity UPLC BEH HILIC column by using isocratic elution with a mobile phase consisting of 10 mmol L(-1) ammonium acetate in acetonitrile-water (95:5, v/v) at a flow rate of 0.5 mL min(-1). Optimization of MSPD extraction parameters, such as type of solid sorbent and elution solvent were carried out. Optimal conditions selected for MSPD extraction were: 0.25 g of feed sample, 0.5 g of octadecylsilica as solid sorbent and 10 mL of acetonitrile-methanol (8:2, v/v) as eluting solvent. Both analytes provided average recoveries from spiked feed samples ranging from 89.1 to 98.4% with relative standard deviations less than 10%. Obtained performance characteristics are comparable to those achieved by liquid-liquid extraction-HPLC with the advantages of being simpler and significantly faster.

Ligand displacement, headspace single-drop microextraction, and capillary electrophoresis for the determination of weak acid dissociable cyanide.

A new method involving ligand displacement, headspace single-drop microextraction (SDME) with in-drop derivatization and capillary electrophoresis (CE) was developed for the determination of weak acid dissociable (WAD) cyanide. WAD metal-cyanide complexes (Ag(CN)(2)(-), Cd(CN)(4)(2-), Cu(CN)(3)(2-), Hg(CN)(2), Hg(CN)(4)(2-), Ni(CN)(4)(2-) and Zn(CN)(4)(2-)) are decomposed with ligand-displacing reagent and the released hydrogen cyanide is extracted from neutral solution (pH 6.5) with an aqueous microdrop (5 microl) containing Ni(II)-NH(3) as derivatization agent. The hydrogen cyanide extracted reacts with Ni(2+) to form a stable and highly UV absorbing tetracyanonickelate anion which is then determined by CE. Among the three different ligand-displacing reagents (i.e., ethylenediamine, dithizone and polyethileneimine) studied none of the reagents used alone releases cyanide completely from all WAD cyanide complexes. Complete recoveries were obtained by the extraction of WAD cyanide from 0.4 mol l(-1) ethylenediamine chloride buffer (pH 6.5) containing 0.001% (wt) dithizone. Proposed system was applied to determine WAD cyanide in industrial wastewater and river waters samples with spiked recoveries in the range of 95.8-104.7%.

Headspace single-drop microextraction with in-drop derivatization and capillary electrophoretic determination for free cyanide analysis.

A new method involving headspace single-drop microextraction (SDME) with in-drop derivatization and CE is developed for the preconcentration and determination of free cyanide. An aqueous microdrop (5 microL) containing Ni(II)-NH(3) (as derivatization agent), sodium carbonate and ammonium pyromellitate (as internal standard) was used as the acceptor phase. The extracted cyanide forms a stable Ni(CN)(4) (2-) complex which is then determined by CE. Common experimental parameters (sample and acceptor phase pH, extraction temperature, extraction time and sample ionic strength) affecting the extraction efficiency were investigated. Using headspace SDME, free cyanide can be effectively extracted from the neutral solutions, i.e. without the acidification of the sample which often is prone to errors due to incomplete liberation and artefactual cyanide production. Proposed SDME-CE method provided about 58-fold enrichment in 20 min. The calibration curve was linear for concentrations of CN(-) in the range from 0.25 to 20 micromol/L (R(2) = 0.997). The LOD (S/N = 3) was estimated to be 0.08 micromol/L of CN(-). Such a detection sensitivity is high enough for free cyanide determination in common environmental and physiological samples. Finally, headspace SDME was applied to determine free cyanide in human saliva and urine samples with spiked recoveries in the range of 91.7-105.6%. The main advantage of this method is that sample clean-up, preconcentration and derivatization procedures can be completed in a single step. In addition, the proposed technique does not require any sample pretreatment and thus is much less susceptible to interferences compared to existing methods.

Characterization of the SDS-induced electroosmotic flow in micellar electrokinetic chromatography with cationic polyelectrolyte-coated capillaries.

Manipulation of the EOF is essential for achieving optimal separations by MEKC. In this paper, we present an extensive investigation of the effect of common experimental conditions on the EOF observed in a capillary coated with poly(diallyldimethylammonium chloride) (PDADMA) polyelectrolyte under MEKC conditions. It was found that highly reproducible cathodal EOF is achieved approximately at or just below the conditional CMC value of SDS in the electrolytes used. At concentrations of SDS greater than the CMC the EOF is independent of pH. The impact of common organic modifiers (ACN, methanol, urea, beta-CD and nonionic surfactant) on the EOF behavior in both a PDADMA-coated capillary and a bare silica capillary is compared. The suppressing effect of organic modifiers on the EOF is much stronger for coated capillary indicating that these compounds additionally reduce the negative charge density on the capillary surface due to alteration of the surfactant coating.

CE determination of small ions: methods and techniques.

This paper provides an overview on the current status of capillary electrophoresis (CE) in the analysis of inorganic and charged small organic species. The various CE strategies used to improve the separation of ionic analytes are summarized. Technical developments in the design of improved detection systems are described. A brief account of their advantages and limitations is given. The potential use of these devices for miniaturized CE systems is also described. Finally, special attention is focused on the on-capillary preconcentration techniques developed in attempts to overcome the poor detectability of CE. Recent review articles are frequently cited to provide readers with a source of information about pioneering work, theoretical treatments, and specific applications.

Silicone glue coated stainless steel wire for solid phase microextraction.

A new solid phase microextraction (SPME) fiber based on high-temperature silicone glue coated on a stainless steel wire is presented. The fiber coating can be prepared easily in a few minutes, it is mechanically stable and exhibits relatively high thermal stability (up to 260 degrees C). The extraction properties of the fiber to benzene, toluene, ethylbenzene, and xylenes (BTEX) were examined using both direct and headspace SPME modes coupled to gas chromatography-flame ionization detection. The effects of the extraction and desorption parameters including extraction and desorption time, sampling and desorption temperature, and ionic strength on the extraction/desorption efficiency have been studied. For both headspace and direct SPME the calibration graphs were linear in the concentration range from 0.5 microg L(-1) to 10 mg L(-1) (R2>0.996) and detection limits ranged from 0.07 to 0.24 microg L(-1). Single fiber repeatability and fiber-to-fiber reproducibility were less than 6.8 and 21.5%, respectively. Finally, headspace SPME was applied to determine BTEX in petrol station waste waters with spiked recoveries in the range of 89.7-105.2%.

Micellar electrokinetic chromatography at low pH with polyelectrolyte-coated capillaries.

The performance of capillaries coated with a poly(diallyldimethylammonium) (PDADMA) monolayer or poly(diallyldimethylammonium)-poly(styrenesulfonate) bilayer was investigated and compared under micellar electrokinetic chromatographic (MEKC) conditions. Both monolayer (positively charged) and bilayer (negatively charged) coatings with micellar (sodium dodecyl sulfate) electrolyte generated very stable and pH-independent cathodal electroosmotic flow (EOF). From the results obtained, it can be concluded that in a doubly coated capillary the second poly(styrenesulfonate) layer is replaced by sodium dodecyl sulfate micelles during flushing with micellar electrolyte. Consequently, in order to obtain a stable and pH-independent cathodal electroosmotic flow for the MEKC separations, the capillary coating with the second polyanion layer is not necessary. The importance of the PDADMA coating was illustrated by comparing MEKC separations of the common developing agents (hydroquinone, phenidone, pyrocatechol, pyrogallol and quinone) on a bare uncoated capillary with the coated capillary. The coating provides reproducible MEKC separations at low pH (pH 3.0) with relative standard deviation (R.S.D.) values for migration times and peak areas lower than 0.45 and 3.3%, respectively. Good linearities in the range from 5 x 10(-5) to 2 x 10(-3) mol l(-1) were obtained for all five compounds, with correlation coefficients higher than 0.998. The detection limits were in the range from 5 x 10(-6) mol l(-1) for pyrocatechol to 2 x 10(-5) mol l(-1) for quinone. The proposed MEKC system was applied to the determination of hydroquinone and phenidone in X-ray photographic developer solutions.

Derivatization of inorganic ions in capillary electrophoresis.

This review gives a short overview of the main approaches to the derivatization of inorganic ions in capillary electrophoresis (CE) with emphasis on the most recent works. Various derivatization procedures and detection methods are discussed. A brief account of their advantages and limitations is given. More specific areas such as microchip CE, simultaneous separation of anions and cations, and speciation analysis are also briefly discussed.

Speciation of Co(II), Co(III), and Cu(II) in ethylenediamine solutions by capillary electrophoresis.

A capillary electrophoretic (CE) method for the speciation of Co(II), Co(III), and Cu(II) in electroless copper-plating baths containing ethylenediamine (En) has been developed. The method is based on the selective pre-capillary derivatization of Co(II) with 1,10-phenanthroline (Phen) followed by CE separation of stable [CoPhen(3)](2+), [CoEn(3)](3+), and [CuEn(2)](2+) chelates. The proposed derivatization procedure protects Co(II) from oxidation by dissolved oxygen and enables rapid determination of all three metal species within a single run. The optimized separations were carried out in a fused silica capillary (57 cmx75-microm I.D.) filled with an ethylenediamine sulfate electrolyte (20 mmol L(-1) H(2)SO(4), pH 7.0 with En, applied voltage +30 kV) using direct UV detection at 214 nm. The detection limits for a signal-to-noise ratio of 3 and 10 s, hydrodynamic injections were 5x10(-6) mol L(-1) for Cu(II), 1x10(-6) mol L(-1) for Co(III), and 4x10(-7) mol L(-1) for Co(II). Application of the method to the speciation of Co(II), Co(III), and Cu(II) in copper-plating bath samples is also demonstrated.

Development of capillary electrophoresis for the determination of metal ions using mixed partial and complete complexation techniques.

A new capillary electrophoretic (CE) method was developed for the selective and sensitive determination of common metal ions. The proposed method is based on conventional CE separation of metal cations followed by complete complexation of separated analytes with 1,10-phenanthroline using the zone-passing technique. This approach combines both partial and complete complexation modes and, thus, enables rapid, selective, efficient separation together with sensitive direct UV detection of metal species. The optimal conditions for the separation and derivatization reaction were established by varying type of electrolyte, electrolyte pH, introduction time and concentration of 1,10-phenanthroline. The optimized separations were carried out in 50 mmol l(-1) glycolic acid electrolyte (pH 6.0 with imidazole) using direct UV detection at 254 nm. Five common metal cations (Fe2+, Co2+, Ni2+, Cu2+ and Zn2+) were separated in less than 4 min. The proposed system was applied to the determination of Fe(II) and Zn(II) in snow samples. The recovery tests established for snow samples were within the range 100+/-12%.

Capillary electrophoretic determination of thiosulfate, sulfide and sulfite using in-capillary derivatization with iodine.

A new capillary electrophoresis (CE) method was developed for the rapid, simple and selective determination of thiosulfate, sulfide and sulfite species. The proposed method is based on the in-capillary derivatization of separated sulfur anions by mixing their zones with the iodine zone during the electrophoretic migration and direct UV detection of iodide formed. The optimal conditions for the separation and derivatization reaction were established by varying electrolyte pH, electrolyte counter-ion, concentration of iodine, and applied voltage. The optimized separations were carried out in 20 mmol/L Tris-chloride electrolyte (pH 8.5) using direct UV detection at 214 nm. All three sulfur species were well resolved in less than 4 min. The method gives repeatability comparable or even better than this obtained for sulfur anions using standard CE technique. The proposed CE system was applied to the monitoring of sulfur anions in spent fixing solutions during the electrolytic oxidation.